The present invention relates to engine mounting apparatus for turbofan jet propulsion engines, particularly to apparatus for mounting the turbofan jet propulsion engine on a wing strut extending downwardly from the wing, and most particularly to an apparatus for supporting the inlet from the jet propulsion engine, an apparatus for coupling the turbofan engine to a wing strut so as to transfer thrust loads along a centerplane of the engine, and to an assembly for transferring axial fan thrust reverser loads through the inlet and back to the engine so that they can be removed along an axial centerplane of the engine.
Turbofan jet propulsion engines are currently attached to wing struts and other airplane structure by a wide variety of different types of linkages, yokes, and mounts. These mounting structures are coupled to the engine at points other than the axial centerplane of the engine, and thus impose thrust-induced bending moments, vertical kick loads, and lateral pinch loads on the engine itself, and particularly on the fan case. When these forces become great enough, the fan case is distorted so that the blade tip seals and the fan blades rub on the interior of the case, a major cause of premature engine deterioration and excessive fuel burn.
Further, the inlet of a strut mounted turbofan engine is generally bolted directly to the fan case of the engine. Aerodynamic and inertial moments imposed on the inlet, as for example occur at rotation of an airplane during takeoff, are thus transferred directly to the engine fan case as a bending moment, again causing blade and tip seal wear and consequent engine deterioration and performance loss.
Additionally, the thrust reverser on a high bypass turbofan engine having a short fan duct and strut mounted nacelle is normally attached directly to the engine fan case. Aerodynamic and inertial loads imposed upon the thrust reverser are not uniformly axially oriented, thus again causing fan case distortion, fan blade and tip seal wear, and consequent engine deterioration and performance loss.
It is therefore an object of the present invention to provide structure for coupling a turbofan jet propulsion engine in an underslung position to a wing strut so that virtually no thrust-induced bending moments, kick loads, or pinch loads are exerted on the engine case, fan case, or other parts of the engine. It is a further object of the present invention to provide engine mounting structure for transferring thrust and other loads from the engine to a strut or other airplane structure on which the engine is mounted only in an axial direction. It is another object of the present invention to prevent bending moments caused by aerodynamic and inertial loads from being transferred from the inlet to the fan case and to provide additional structure for transferring nonaxial components of these loads directly from the inlet to the wing strut. It is a further object of the present invention to isolate the engine from bending moments produced by the fan thrust reverser on a high bypass turbofan engine. Conjunctively, it is yet a further object of the present invention to transfer a portion of such bending moments to the inlet and to transfer only axially oriented portions of a moment couple back to the engine fan case and thus to the strut through the engine mounting structure.